IPA: /ˈræt.əl.ɪŋ.li/
KK: /ˈrætəlɪŋli/
In a way that produces a loud, sharp sound, often associated with shaking or moving quickly.
The old train moved rattlingly down the tracks, making a loud noise.
Rattlingly → It is formed from "rattle" (of imitative origin, representing the sound made) and "-ingly" (a suffix used to form adverbs indicating manner). The word "rattlingly" describes an action done in a manner that produces a rattling sound.
Imagine something making a loud, shaking noise — that's what 'rattlingly' means, as it describes an action done in a rattling manner.